Quote:
Originally Posted by krystar
continuing where i left off 2*(1+2+...+n) ?=? [n+1]*n
2*n*(n+1)/2 ?=? [n+1]*n
{cancel out 2}
n*(n+1) ?=? n*n [you mean n*(n+1) = n*(n+1)]
YES! finished it hehe
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Very good. I didn't check your entire proof, but the realization that "1+2+...+n = n*(n+1)/2" by Carl Gauss is key.